As adults, there are things we understand that we did not as children. Children are still, by their very nature, trying to understand the world. The problem is, they may also believe they already have such understanding, even understanding beyond that of their surrounding adults. We've all been there. From typical childish beliefs, such as "broccoli is evil", to silly beliefs that are almost unique to each individual child, all of us perceived the world differently as children than we now do as adults.
Although children do not usually respond this way, a wise child will both accept that their parents understand the world better than they do, and be totally ok with this fact. It is not necessarily wrong for them to want to ask questions, but it is very childish to insist that, because they do not understand the way things are, therefore things must be some other way.
Even as adults, we are like children to God. There are many things we do not understand, and while it is not wrong for us to want to ask questions, the wise thing to do is just trust God. We may not understand why God gives a specific command, but nevertheless He gave it, and so the right thing to do is obey Him as a child obeys a parent. We may not understand a complex doctrine, such as the Trinity, but that doesn't give us the right to try to alter it to suit our understanding. There may even be things about Christianity that we completely despise, but true wisdom is to accept that we are wrong to despise it.
There are things children do not understand that they will understand as adults. There are things the living do not understand that they will understand after death. In the mean time, we who are waiting for this knowledge should be ok with not yet possessing it. Do as a wise child does: Listen to God, and grow.